linux-stable/include/linux/crush/crush.h

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License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 14:07:57 +00:00
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef CEPH_CRUSH_CRUSH_H
#define CEPH_CRUSH_CRUSH_H
#ifdef __KERNEL__
# include <linux/rbtree.h>
# include <linux/types.h>
#else
# include "crush_compat.h"
#endif
/*
* CRUSH is a pseudo-random data distribution algorithm that
* efficiently distributes input values (typically, data objects)
* across a heterogeneous, structured storage cluster.
*
* The algorithm was originally described in detail in this paper
* (although the algorithm has evolved somewhat since then):
*
* https://www.ssrc.ucsc.edu/Papers/weil-sc06.pdf
*
* LGPL2
*/
#define CRUSH_MAGIC 0x00010000ul /* for detecting algorithm revisions */
#define CRUSH_MAX_DEPTH 10 /* max crush hierarchy depth */
#define CRUSH_MAX_RULESET (1<<8) /* max crush ruleset number */
#define CRUSH_MAX_RULES CRUSH_MAX_RULESET /* should be the same as max rulesets */
#define CRUSH_MAX_DEVICE_WEIGHT (100u * 0x10000u)
#define CRUSH_MAX_BUCKET_WEIGHT (65535u * 0x10000u)
#define CRUSH_ITEM_UNDEF 0x7ffffffe /* undefined result (internal use only) */
#define CRUSH_ITEM_NONE 0x7fffffff /* no result */
/*
* CRUSH uses user-defined "rules" to describe how inputs should be
* mapped to devices. A rule consists of sequence of steps to perform
* to generate the set of output devices.
*/
struct crush_rule_step {
__u32 op;
__s32 arg1;
__s32 arg2;
};
/* step op codes */
enum {
CRUSH_RULE_NOOP = 0,
CRUSH_RULE_TAKE = 1, /* arg1 = value to start with */
CRUSH_RULE_CHOOSE_FIRSTN = 2, /* arg1 = num items to pick */
/* arg2 = type */
CRUSH_RULE_CHOOSE_INDEP = 3, /* same */
CRUSH_RULE_EMIT = 4, /* no args */
CRUSH_RULE_CHOOSELEAF_FIRSTN = 6,
CRUSH_RULE_CHOOSELEAF_INDEP = 7,
CRUSH_RULE_SET_CHOOSE_TRIES = 8, /* override choose_total_tries */
CRUSH_RULE_SET_CHOOSELEAF_TRIES = 9, /* override chooseleaf_descend_once */
CRUSH_RULE_SET_CHOOSE_LOCAL_TRIES = 10,
CRUSH_RULE_SET_CHOOSE_LOCAL_FALLBACK_TRIES = 11,
CRUSH_RULE_SET_CHOOSELEAF_VARY_R = 12,
CRUSH_RULE_SET_CHOOSELEAF_STABLE = 13
};
/*
* for specifying choose num (arg1) relative to the max parameter
* passed to do_rule
*/
#define CRUSH_CHOOSE_N 0
#define CRUSH_CHOOSE_N_MINUS(x) (-(x))
/*
* The rule mask is used to describe what the rule is intended for.
* Given a ruleset and size of output set, we search through the
* rule list for a matching rule_mask.
*/
struct crush_rule_mask {
__u8 ruleset;
__u8 type;
__u8 min_size;
__u8 max_size;
};
struct crush_rule {
__u32 len;
struct crush_rule_mask mask;
libceph, rbd: replace zero-length array with flexible-array The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] sizeof(flexible-array-member) triggers a warning because flexible array members have incomplete type[1]. There are some instances of code in which the sizeof operator is being incorrectly/erroneously applied to zero-length arrays and the result is zero. Such instances may be hiding some bugs. So, this work (flexible-array member conversions) will also help to get completely rid of those sorts of issues. This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Reviewed-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2020-05-07 18:51:38 +00:00
struct crush_rule_step steps[];
};
#define crush_rule_size(len) (sizeof(struct crush_rule) + \
(len)*sizeof(struct crush_rule_step))
/*
* A bucket is a named container of other items (either devices or
* other buckets). Items within a bucket are chosen using one of a
* few different algorithms. The table summarizes how the speed of
* each option measures up against mapping stability when items are
* added or removed.
*
* Bucket Alg Speed Additions Removals
* ------------------------------------------------
* uniform O(1) poor poor
* list O(n) optimal poor
* tree O(log n) good good
* straw O(n) better better
* straw2 O(n) optimal optimal
*/
enum {
CRUSH_BUCKET_UNIFORM = 1,
CRUSH_BUCKET_LIST = 2,
CRUSH_BUCKET_TREE = 3,
CRUSH_BUCKET_STRAW = 4,
CRUSH_BUCKET_STRAW2 = 5,
};
extern const char *crush_bucket_alg_name(int alg);
/*
* although tree was a legacy algorithm, it has been buggy, so
* exclude it.
*/
#define CRUSH_LEGACY_ALLOWED_BUCKET_ALGS ( \
(1 << CRUSH_BUCKET_UNIFORM) | \
(1 << CRUSH_BUCKET_LIST) | \
(1 << CRUSH_BUCKET_STRAW))
struct crush_bucket {
__s32 id; /* this'll be negative */
__u16 type; /* non-zero; type=0 is reserved for devices */
__u8 alg; /* one of CRUSH_BUCKET_* */
__u8 hash; /* which hash function to use, CRUSH_HASH_* */
__u32 weight; /* 16-bit fixed point */
__u32 size; /* num items */
__s32 *items;
};
crush: implement weight and id overrides for straw2 bucket_straw2_choose needs to use weights that may be different from weight_items. For instance to compensate for an uneven distribution caused by a low number of values. Or to fix the probability biais introduced by conditional probabilities (see http://tracker.ceph.com/issues/15653 for more information). We introduce a weight_set for each straw2 bucket to set the desired weight for a given item at a given position. The weight of a given item when picking the first replica (first position) may be different from the weight the second replica (second position). For instance the weight matrix for a given bucket containing items 3, 7 and 13 could be as follows: position 0 position 1 item 3 0x10000 0x100000 item 7 0x40000 0x10000 item 13 0x40000 0x10000 When crush_do_rule picks the first of two replicas (position 0), item 7, 3 are four times more likely to be choosen by bucket_straw2_choose than item 13. When choosing the second replica (position 1), item 3 is ten times more likely to be choosen than item 7, 13. By default the weight_set of each bucket exactly matches the content of item_weights for each position to ensure backward compatibility. bucket_straw2_choose compares items by using their id. The same ids are also used to index buckets and they must be unique. For each item in a bucket an array of ids can be provided for placement purposes and they are used instead of the ids. If no replacement ids are provided, the legacy behavior is preserved. Reflects ceph.git commit 19537a450fd5c5a0bb8b7830947507a76db2ceca. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2017-06-22 17:44:05 +00:00
/** @ingroup API
*
* Replacement weights for each item in a bucket. The size of the
* array must be exactly the size of the straw2 bucket, just as the
* item_weights array.
*
*/
struct crush_weight_set {
__u32 *weights; /*!< 16.16 fixed point weights
in the same order as items */
__u32 size; /*!< size of the __weights__ array */
};
/** @ingroup API
*
* Replacement weights and ids for a given straw2 bucket, for
* placement purposes.
*
* When crush_do_rule() chooses the Nth item from a straw2 bucket, the
* replacement weights found at __weight_set[N]__ are used instead of
* the weights from __item_weights__. If __N__ is greater than
* __weight_set_size__, the weights found at __weight_set_size-1__ are
* used instead. For instance if __weight_set__ is:
*
* [ [ 0x10000, 0x20000 ], // position 0
* [ 0x20000, 0x40000 ] ] // position 1
*
* choosing the 0th item will use position 0 weights [ 0x10000, 0x20000 ]
* choosing the 1th item will use position 1 weights [ 0x20000, 0x40000 ]
* choosing the 2th item will use position 1 weights [ 0x20000, 0x40000 ]
* etc.
*
*/
struct crush_choose_arg {
__s32 *ids; /*!< values to use instead of items */
__u32 ids_size; /*!< size of the __ids__ array */
struct crush_weight_set *weight_set; /*!< weight replacements for
a given position */
__u32 weight_set_size; /*!< size of the __weight_set__ array */
};
/** @ingroup API
*
* Replacement weights and ids for each bucket in the crushmap. The
* __size__ of the __args__ array must be exactly the same as the
* __map->max_buckets__.
*
* The __crush_choose_arg__ at index N will be used when choosing
* an item from the bucket __map->buckets[N]__ bucket, provided it
* is a straw2 bucket.
*
*/
struct crush_choose_arg_map {
#ifdef __KERNEL__
struct rb_node node;
s64 choose_args_index;
#endif
crush: implement weight and id overrides for straw2 bucket_straw2_choose needs to use weights that may be different from weight_items. For instance to compensate for an uneven distribution caused by a low number of values. Or to fix the probability biais introduced by conditional probabilities (see http://tracker.ceph.com/issues/15653 for more information). We introduce a weight_set for each straw2 bucket to set the desired weight for a given item at a given position. The weight of a given item when picking the first replica (first position) may be different from the weight the second replica (second position). For instance the weight matrix for a given bucket containing items 3, 7 and 13 could be as follows: position 0 position 1 item 3 0x10000 0x100000 item 7 0x40000 0x10000 item 13 0x40000 0x10000 When crush_do_rule picks the first of two replicas (position 0), item 7, 3 are four times more likely to be choosen by bucket_straw2_choose than item 13. When choosing the second replica (position 1), item 3 is ten times more likely to be choosen than item 7, 13. By default the weight_set of each bucket exactly matches the content of item_weights for each position to ensure backward compatibility. bucket_straw2_choose compares items by using their id. The same ids are also used to index buckets and they must be unique. For each item in a bucket an array of ids can be provided for placement purposes and they are used instead of the ids. If no replacement ids are provided, the legacy behavior is preserved. Reflects ceph.git commit 19537a450fd5c5a0bb8b7830947507a76db2ceca. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2017-06-22 17:44:05 +00:00
struct crush_choose_arg *args; /*!< replacement for each bucket
in the crushmap */
__u32 size; /*!< size of the __args__ array */
};
struct crush_bucket_uniform {
struct crush_bucket h;
__u32 item_weight; /* 16-bit fixed point; all items equally weighted */
};
struct crush_bucket_list {
struct crush_bucket h;
__u32 *item_weights; /* 16-bit fixed point */
__u32 *sum_weights; /* 16-bit fixed point. element i is sum
of weights 0..i, inclusive */
};
struct crush_bucket_tree {
struct crush_bucket h; /* note: h.size is _tree_ size, not number of
actual items */
__u8 num_nodes;
__u32 *node_weights;
};
struct crush_bucket_straw {
struct crush_bucket h;
__u32 *item_weights; /* 16-bit fixed point */
__u32 *straws; /* 16-bit fixed point */
};
struct crush_bucket_straw2 {
struct crush_bucket h;
__u32 *item_weights; /* 16-bit fixed point */
};
/*
* CRUSH map includes all buckets, rules, etc.
*/
struct crush_map {
struct crush_bucket **buckets;
struct crush_rule **rules;
__s32 max_buckets;
__u32 max_rules;
__s32 max_devices;
/* choose local retries before re-descent */
__u32 choose_local_tries;
/* choose local attempts using a fallback permutation before
* re-descent */
__u32 choose_local_fallback_tries;
/* choose attempts before giving up */
__u32 choose_total_tries;
/* attempt chooseleaf inner descent once for firstn mode; on
* reject retry outer descent. Note that this does *not*
* apply to a collision: in that case we will retry as we used
* to. */
libceph: for chooseleaf rules, retry CRUSH map descent from root if leaf is failed Add libceph support for a new CRUSH tunable recently added to Ceph servers. Consider the CRUSH rule step chooseleaf firstn 0 type <node_type> This rule means that <n> replicas will be chosen in a manner such that each chosen leaf's branch will contain a unique instance of <node_type>. When an object is re-replicated after a leaf failure, if the CRUSH map uses a chooseleaf rule the remapped replica ends up under the <node_type> bucket that held the failed leaf. This causes uneven data distribution across the storage cluster, to the point that when all the leaves but one fail under a particular <node_type> bucket, that remaining leaf holds all the data from its failed peers. This behavior also limits the number of peers that can participate in the re-replication of the data held by the failed leaf, which increases the time required to re-replicate after a failure. For a chooseleaf CRUSH rule, the tree descent has two steps: call them the inner and outer descents. If the tree descent down to <node_type> is the outer descent, and the descent from <node_type> down to a leaf is the inner descent, the issue is that a down leaf is detected on the inner descent, so only the inner descent is retried. In order to disperse re-replicated data as widely as possible across a storage cluster after a failure, we want to retry the outer descent. So, fix up crush_choose() to allow the inner descent to return immediately on choosing a failed leaf. Wire this up as a new CRUSH tunable. Note that after this change, for a chooseleaf rule, if the primary OSD in a placement group has failed, choosing a replacement may result in one of the other OSDs in the PG colliding with the new primary. This requires that OSD's data for that PG to need moving as well. This seems unavoidable but should be relatively rare. This corresponds to ceph.git commit 88f218181a9e6d2292e2697fc93797d0f6d6e5dc. Signed-off-by: Jim Schutt <jaschut@sandia.gov> Reviewed-by: Sage Weil <sage@inktank.com>
2012-11-30 16:15:25 +00:00
__u32 chooseleaf_descend_once;
/* if non-zero, feed r into chooseleaf, bit-shifted right by (r-1)
* bits. a value of 1 is best for new clusters. for legacy clusters
* that want to limit reshuffling, a value of 3 or 4 will make the
* mappings line up a bit better with previous mappings. */
__u8 chooseleaf_vary_r;
/* if true, it makes chooseleaf firstn to return stable results (if
* no local retry) so that data migrations would be optimal when some
* device fails. */
__u8 chooseleaf_stable;
/*
* This value is calculated after decode or construction by
* the builder. It is exposed here (rather than having a
* 'build CRUSH working space' function) so that callers can
* reserve a static buffer, allocate space on the stack, or
* otherwise avoid calling into the heap allocator if they
* want to. The size of the working space depends on the map,
* while the size of the scratch vector passed to the mapper
* depends on the size of the desired result set.
*
* Nothing stops the caller from allocating both in one swell
* foop and passing in two points, though.
*/
size_t working_size;
#ifndef __KERNEL__
/*
* version 0 (original) of straw_calc has various flaws. version 1
* fixes a few of them.
*/
__u8 straw_calc_version;
/*
* allowed bucket algs is a bitmask, here the bit positions
* are CRUSH_BUCKET_*. note that these are *bits* and
* CRUSH_BUCKET_* values are not, so we need to or together (1
* << CRUSH_BUCKET_WHATEVER). The 0th bit is not used to
* minimize confusion (bucket type values start at 1).
*/
__u32 allowed_bucket_algs;
__u32 *choose_tries;
#else
/* device/bucket type id -> type name (CrushWrapper::type_map) */
struct rb_root type_names;
/* device/bucket id -> name (CrushWrapper::name_map) */
struct rb_root names;
/* CrushWrapper::choose_args */
struct rb_root choose_args;
#endif
};
/* crush.c */
extern int crush_get_bucket_item_weight(const struct crush_bucket *b, int pos);
extern void crush_destroy_bucket_uniform(struct crush_bucket_uniform *b);
extern void crush_destroy_bucket_list(struct crush_bucket_list *b);
extern void crush_destroy_bucket_tree(struct crush_bucket_tree *b);
extern void crush_destroy_bucket_straw(struct crush_bucket_straw *b);
extern void crush_destroy_bucket_straw2(struct crush_bucket_straw2 *b);
extern void crush_destroy_bucket(struct crush_bucket *b);
extern void crush_destroy_rule(struct crush_rule *r);
extern void crush_destroy(struct crush_map *map);
static inline int crush_calc_tree_node(int i)
{
return ((i+1) << 1)-1;
}
/*
* These data structures are private to the CRUSH implementation. They
* are exposed in this header file because builder needs their
* definitions to calculate the total working size.
*
* Moving this out of the crush map allow us to treat the CRUSH map as
* immutable within the mapper and removes the requirement for a CRUSH
* map lock.
*/
struct crush_work_bucket {
__u32 perm_x; /* @x for which *perm is defined */
__u32 perm_n; /* num elements of *perm that are permuted/defined */
__u32 *perm; /* Permutation of the bucket's items */
};
struct crush_work {
struct crush_work_bucket **work; /* Per-bucket working store */
#ifdef __KERNEL__
struct list_head item;
#endif
};
#ifdef __KERNEL__
/* osdmap.c */
void clear_crush_names(struct rb_root *root);
void clear_choose_args(struct crush_map *c);
#endif
#endif